1. Field of the Invention
This invention relates to a combination needle shield/needle guard device which is positively locked onto a (1) detachable double-ended needle assembly used for an evacuated blood collection system and (2) a detachable needle assembly for a hypodermic syringe. More particularly, this combination needle shield/needle guard device can function as a needle shield to enclose and prevent contamination of a sterile needle to be used for insertion into the skin and/or blood vessel of a patient. In addition, the needle shield/needle guard device can function as a needle guard which can slide on the needle assemblies, so that the needle can be uncovered or re-covered in a direction from behind the needle point, thereby providing a safety feature for the operator who can avoid direct contact with a used, blood-contaminated needle point.
2. Description of the Prior Art
There are many types of removeable needle shields which cover needles used with conventional syringes or are used to cover a double-ended needle assembly with an evacuated blood collection system. Examples include the following references selected from the U.S. Patent and Trademark Office: U.S. Pat. Nos. 3,381,813; 3,934,722; 4,113,090; 4,121,588; 3,734,080; and 3,931,815. These removeable needle shields reveal several limitations such as: (1) after removal of the needle shield from the needle attached to a syringe, medical personnel may occasionally delay the usage of the needle in a procedure, which would require replacement of the needle shield back over the needle to prevent contamination of the sterile needle. This maneuver requires keeping track of the removed needle shield and then replacing the needle shield over the needle, which represent extra steps for busy medical personnel. Replacing the needle shield over the needle point also increases the risk for self-puncture with the needle point; (2) another common practice occurs when medical personnel remove this type of needle shield by holding the needle shield between their teeth or lips. This maneuver has been associated with accidental self-puncture in the face or other bodily parts; (3) in order to remove a used double-ended needle assembly from a reuseable container holder of an evacuated blood collection system, it is necessary to re-cover the used needle with a needle shield and then unfasten the double-ended needle assembly from the reusable container holder. Similarly, to remove a used needle that is luer-locked to a syringe barrel, it is necessary to re-cover the needle with a needle shield and then unfasten the needle from the syringe barrel. Both procedures require that the user replace the needle shield over the pointed end of the used needle, which increases the risk to medical personnel who may accidentally puncture themselves with the pointed end of the used, blood contaminated needle; (4) when the needle shield is replaced over the used needle, if the needle has been accidentally bent during a medical procedure or if the needle shield is replaced over the needle at an incorrect angle, the needle point may inadvertently pierce the side of the needle shield as it is being replaced over the needle. The operator using the needle shield could be punctured with a used blood-contaminated needle point that has exteriorized through a needle shield; and (5) most laboratories use containers with or without a clip-off needle device to store used needles. Personnel may puncture themselves with used uncovered needles that may accidentally fall out of these storage containers or with uncovered needles that are disposed of inappropriately in waste baskets. In addition, if the storage container is full, it is possible to accidentally puncture oneself with a used, uncovered needle that is pointed towards the opening of the storage container.
Another device relevant to our invention includes U.S. Pat. No. 4,425,120 issued to Sampson et al which describes a needle guard device which is attached to a conventional hypodermic syringe or apparatus used for injecting a substance into a human or animal. This device functions as a slideable needle guard to uncover or re-cover a used needle. This needle guard has an open-end, which precludes its routine use to function also as a needle shield to enclose and prevent contamination of a sterile needle. In order to prevent contamination of the sterile needle in this device, it would be necessary to cover the needle with a separate needle shield, or close the opening of the needle guard with a material which must be ruptured by the needle or needle shield enclosing the needle. In addition, this needle guard device is not adapted to remove a used double-ended needle assembly from a container holder or to remove a used hypodermic syringe needle assembly from a syringe barrel. Thus, in both situations a separate needle shield would still be required to re-cover and unfasten the detachable needle assemblies, thereby increasing the risk for self-puncture with a used needle point.
Another needle guard device, U.S. Pat. No. 4,139,009 issued to Alvarez, is composed of four longitudinal arms which are brought into lateral side-to-side contact with the intention of covering and protecting the enclosed needle. The front end of the cover and the lateral arms in side-to-side contact represent discontinuous locations which could permit microorganism penetration and contamination of the enclosed sterile needle. When this device is pushed against a skin surface during the injection process, the arms must bow away from the longitudinal axis of the needle which could block visualization of the needle as it penetrates the skin. It is important that the operator attempting to draw blood be able to clearly visualize a blood vessel. In addition, this needle guard device is not adapted to remove a used double-ended needle assembly from a container holder or to remove a used needle assembly from a hypodermic syringe barrel. Thus, in both situations a needle shield would still be required to re-cover and unfasten the detachable needle assemblies, thereby increasing the risk for self-puncture with a used needle point.
Examples in the U.S. Patent and Trademark Office of evacuated blood collection systems with a removeable needle shield are U.S. Pat. Nos. 2,460,641, 3,931,815, 4,154,229, 4,295,476, 4,295,477, 4,312,362, and 4,340,068. Operators of a blood evacuated collection system with a double-ended needle assembly must re-cover a used needle over the pointed end of the needle with a needle shield in order to unfasten the double-ended needle assembly from the reusable container holder. This maneuver can cause puncture with contaminated needles with the subsequent risk of developing blood-borne infections, such as AIDS, infectious hepatitis, syphilis, etc. Similar risks occur for the operator of a hypodermic syringe who must replace a needle shield over the detachable needle assembly in order to remove the used needle from the syringe barrel. Therefore during the procedure of removing used needle assemblies from an evacuated blood collection system or hypodermic syringe, it is desireable to provide a mechanism whereby the operator of either device can be safeguarded from causing self-puncture with a used, blood contaminated needle point.
There are other identifiable problems with currently used blood evacuation collection systems. The container holder used in the blood evacuated collection system exhibits several limitations that can interfere in successful blood withdrawing procedures. On occasion operators of an evacuated blood collection system have experienced the unfortunate occurrence in which the double-ended needle assembly has unfastened from the container holder. This may occur during the following circumstances: (1) the first needle of the double-ended needle assembly has penetrated into a blood vessel; (2) the operator has begun to move an evacuated container forward into the container holder so that the inner needle (i.e. second needle) of the double-ended needle assembly can penetrate through the evacuated container stopper; (3) during step 2, the force of pushing on the second needle causes the threads on the housing of the double-ended needle assembly to unwind from the internal mating threads at the forward end of the container holder, thereby causing the entire double-ended needle assembly to disengage from the container holder. There are several explanations for the disengagement of these parts such as: (1) the threads of the housing of the double-ended needle assembly are not tightened properly into the internal mating threads of the container holder; and/or (2) the internal mating threads of the container holder can become worn from frequent usage which would subsequently prevent adequate securing between the housing of the double-ended needle assembly and the container holder. It is thus desireable to provide a mechanism to eliminate this problem by using an improved locking system between the double-ended needle assembly housing and the container holder.
Another problem which develops using a blood evacuated collection system concerns the positioning of the first needle into a blood vessel. The wide girth of the container holder can cause the operator to direct the needle in a less acute angulation in respect to the planar surface of the skin, thereby causing the needle point to puncture the blood vessel wall at a higher, less acute angle that will more easily lead to puncturing through the opposite wall of the blood vessel. If such an event occurs, it may be difficult to withdraw blood from the blood vessel, as well as cause subsequent blood leakage around the blood vessel i.e. hematomas. A similar problem can occur for the user of a hypodermic syringe, especially for large volume syringes with a wide diameter of the syringe barrel. It is therefore desireable to eliminate the configuration restrictions imposed by a wide girth container holder or barrel of a hypodermic syringe which make it difficult for the operator to direct the needle in a more shallow or acute angle in respect to the planar surface of the skin.